SAF-C164SM Infineon Technologies, SAF-C164SM Datasheet - Page 160

• Manufacturer Part Number: SAF-C164SM
• Description: 16-Bit CMOS Microcontroller
• Manufacturer: Infineon Technologies

ODP8
P8 Open Drain Ctrl. Reg.
Bit
ODP8.y
Alternate Functions of Port 8
All Port 8 lines serve as capture inputs or compare outputs (CCxIO) for the CAPCOM2
unit (see
When a Port 8 line is used as a capture input, the state of the input latch, representing
the state of the port pin, is directed to the CAPCOM unit via the line “Alternate Pin Data
Input”. If an external capture trigger signal is used, the direction of the respective pin
must be set to input. If the direction is set to output, the state of the port output latch will
be read, because the pin represents the state of the output latch. This can be used to
trigger a capture event through software by setting or clearing the port latch. Note that
in the output configuration, no external device may drive the pin, otherwise conflicts
would occur.
When a Port 8 line is used as a compare output (compare modes 1 and 3), the compare
event (or the timer overflow in compare mode 3) directly affects the port output latch. In
compare mode 1, when a valid compare match occurs, the state of the port output latch
is read by the CAPCOM control hardware via the line “Alternate Latch Data Input”, is
inverted, and then written back to the latch via the line “Alternate Data Output”. The port
output latch is clocked by the signal “Compare Trigger” which is generated by the
CAPCOM unit. In compare mode 3, when a match occurs, the value ‘1’ is written to the
port output latch via the line “Alternate Data Output”. When an overflow of the
corresponding timer occurs, a ‘0’ is written to the port output latch. In both cases, the
output latch is clocked by the signal “Compare Trigger”. The direction of the pin should
be set to output by the user; otherwise, the pin will be in the high-impedance state and
will not reflect the state of the output latch.
As can be seen from the port structure below, the user software always has free access
to the port pin even when it is used as a compare output. This is useful for setting up the
initial level of the pin when using compare mode 1 or the double-register mode. In these
modes, unlike in compare mode 3, the pin is not set to a specific value when a compare
match occurs, but is toggled instead.
User’s Manual
15
-
14
-
Table
13
-
Function
Port 8 Open Drain control register bit y
ODP8.y = 0: Port line P8.y output driver in push/pull mode
ODP8.y = 1: Port line P8.y output driver in open drain mode
7-5).
12
-
11
-
10
-
ESFR (F1D6
9
-
8
-
7-25
7
-
-
H
/EB
6
-
-
H
)
5
-
-
4
-
-
ODP8
Reset Value: - - 00
C164CM/C164SM
rw
.3
3
ODP8
rw
Parallel Ports
.2
2
Derivatives
V1.0, 2002-02
ODP8
rw
.1
1
ODP8
rw
.0
0
H